In a conventional semiconductor package, in order to dissipate heat from the device with ease, a heat-exchanging portion is formed by overlaying a molded package with either a heat dissipation panel, or a panel with pins. A panel having heat dissipation pins can also be attached to a leadframe paddle.
A partial sectional view of the latter conventional package described above, is illustrated in FIG. 1. A heat dissipation plate 11 is attached to a back portion of semiconductor chip 10, and molding compound 12 is then used to enclose chip 10 and its signal leads.
In the structure of the conventional semiconductor package manufactured by such method, the heat generated in an upper part of the chip may not be transferred easily to heat dissipation plate 11 through the bottom of the chip. Therefore, in such a structure the heat cannot be dissipated efficiently.
The method in which a molded package is overlaid with either a heat dissipation panel or a panel with pins, is an ineffective heat sink because the heat dissipation plate is attached to the molding compound which typically has a high heat resistance.